There is a dynamic equilibrium between viral production and clearance in untreated chronic hepatitis C viral infection. However, once patients begin antiviral treatment a multiphasic decay of viremia can be observed.
In this study, researchers examined the antiviral mechanism of ribavirin, when used in combination with (pegylated) interferon alpha.
|Viral decay was faster in patients treated with peginterferon alpha-2a and ribavirin.|
The team evaluated patients with chronic hepatitis C who were treated with peginterferon alpha-2a, with or without ribavirin, or standard interferon alpha-2b plus ribavirin, for 48 weeks.
Their results are published in the June issue of Hepatology.
The team measured serum HCV RNA before, during, and at the end-of-treatment, as well as during the follow-up period.
They used a model for viral dynamics, and derived kinetic parameters from nonlinear, least square fitting of serum HCV RNA quantifications.
The researchers found that the first phase of viral decay (day 1), and the second phase of viral decay (days 2 to 21) were similar in all groups.
However, after between 7 and 28 days, a third phase of viral decay was seen in several patients. The team observed that this was significantly faster in patients treated with peginterferon alpha-2a plus ribavirin, compared with those treated with peginterferon alpha-2a alone.
The team determined that this third phase was associated with the virologic end-of-treatment response and sustained virologic response.
Dr Eva Herrmann's team concluded, "The third-phase decay of initial viral kinetics, which may represent a treatment-enhanced degradation of infected cells, was more pronounced in patients treated with peginterferon alpha-2a plus ribavirin".
"This finding suggests that combination treatment leads to a better restoration of the patient's immune response".